WP cron and update post meta

I try to create a scheduled cron job which runs every hour, Its my first time working with wp-cron.

In the cron function, I want to update post meta values, if some conditions are met.

I also tested the code of the cron function outside of the cron to see/print the results. The results looked ok, but when the cronjob runs no post gets updated.

Iam using WP Crontrol to see the all available cronjobs.

First I schedule an event (this seems to works):

function prfx_hourly_status_update_cron_job() {
    if ( ! wp_next_scheduled( 'prfx_run_hourly_status_update_cron_job' ) ) {
        wp_schedule_event( current_time( 'timestamp' ), 'hourly', 'prfx_run_hourly_status_update_cron_job' );
    }
}
add_action( 'wp', 'prfx_hourly_status_update_cron_job' );

After creating this event I than try to run this function.

I get all posts which have a meta field where the value is not empty.
This field is an date. (Y-m-d)
For each post/product I than get two meta values.
The deadline-date and a sooner deadline-soon-date.
I than compare the todays date with these saved dates and want to update another meta value based on this.

function prfx_run_hourly_status_update_cron_job( ) {

    // create meta query to get all posts which have a deadline date (field not empty)
    $args = array(
        'posts_per_page'   => -1,
        'meta_query' => array(
            array(
                'key' => '_prfx_custom_product_deadline',
                'value'   => '',
                'compare' => '!='
            ),
        ),
        'post_type' => 'product',
        'no_found_rows' => true, //speeds up a query significantly and can be set to 'true' if we don't use pagination
        'fields' => 'ids', //again, for performance
    );
    $posts_array = get_posts( $args );

    // start if we have posts
    if ($posts_array) {

        // get todays date in Y-m-d format
        $today = date('Y-m-d');

        //now check conditions and update the code
        foreach( $posts_array as $post_id ){

            $saved_deadline = get_post_meta( $post_id, '_prfx_custom_product_deadline', true ); // get deadline-date
            $soon_deadline = get_post_meta( $post_id, '_prfx_custom_product_deadline_soon', true );// get deadline-soon-date

            if ($today > $saved_deadline) { // if today is after deadline
                update_post_meta( $post_id, '_prfx_custom_product_status', 'deadline-met' );
            } elseif ($today < $saved_deadline && $today > $soon_deadline) { // if today is before deadline but after soon-deadline
                update_post_meta( $post_id, '_prfx_custom_product_status', 'deadline-soon' );
            }

        }
    }
}

As said above I tried to dry run this function, instead of update_post_meta I just printed the data out. This seems to work. Iam also using a similar function to echo out some strings on the frontend, so the date compare also works.

---

Update: So, I cant get this to work with the cronjobs. I just tested the following code inside an plugin, as I activate the plugin, the code runs.
The query is working fine, I printed/checked the results, and it is working as simple plugin code.

But the same code is not running in the cronjob. When I look at the cron output with Wp Crontrol, I can see the hourly event “prfx_run_hourly_status_update_cron_job”, but without any action assigned. However, for example “woocommerce_geoip_updater” has also no action listed.
Maybe someone has an idea why?

Here is the tested code:

add_action('init','prfx_resave_posts');
function prfx_resave_posts(){

    $args = array(
        'posts_per_page'   => -1,
        'post_type'        => 'product',
        'meta_query' => array(
            array(
                'key' => '_prfx_custom_product_deadline_soon',
                'value'   => '',
                'compare' => '!='
            ),
        ),
        'no_found_rows' => true, //speeds up a query significantly and can be set to 'true' if we don't use pagination
        'fields' => 'ids', //again, for performance
    );
    $posts_array = get_posts( $args );

    if ($posts_array) { //output: Array ( [0] => 120399 [1] => 120431 [2] => 120469 [3] => 120401 [4] => 120433 )

        // get todays date in Y-m-d format
        $today = date('Y-m-d');

        foreach ($posts_array as $my_post) {

            #print_r($my_post);
            //output example: 120399

            $saved_soon_deadline = get_post_meta( $my_post, '_prfx_custom_product_deadline_soon', true );

            #print_r($saved_soon_deadline);
            //output: 2018-11-30

            if ($today > $saved_soon_deadline) {
                update_post_meta( $my_post, '_prfx_custom_product_status', 'my-new-val-here' );
            }

        }
    }

}